Lock-top container



M. P. KERNAHAN LOCK-TOP CONTAINER Filed Aug. 24. 1955 July 5, 1938.

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ATTOR Patented July 5, 1938 UNITED STATES PATENT OFFICE LOCK-TOP CONTAINER Martin P. Kernahan, Phillipsburg,

N. 1., assignor to The Canister Company, Phillipsburg, N. 1., a corporation of New Jersey Application August 24, 1935, Serial No. 37,641

6 Claims.

5 thread connection. Lock-top containers of this kind are common in the art in which the paper body is provided with a metal edging or trim on which are formed 'the inclined ribs or screw threads to interlock with corresponding ribs on l the metal cover, the interlock being between two metallic parts.

The object of this invention is to produce a similar and equally satisfactory container in which the metal trim is eliminated and the cover .5 attaches direct to the paper. body, thus affording a substantial saving in manufacturing cost. Previous attempts to produce such low cost lock-top containers have met with no commercial favor principally because the wall or rim of the paper body having the screw thread ribs embossed thereon could not easily be made rigid enough to prevent the ribs on the cover from pulling or riding over them,- thus releasing the interlock. By this invention this'objection is eliminated and the cover can be attached and removed with practically the same facility and security as with a metal-to-metal interlock.

By paper as herein used is meant any ordinary paper-stock or like fibrous material such as com- 0 monly'used for making paper cans or containers and the term metal cover, as herein used,

comprehends covers made of any similar or hard material. I

The container illustrated in the accompanying 5- drawing will suflice to exemplify the principles of the invention it being understood that there is no limitation to this particular form except as required by the claims. In such drawing Fig. 1 is a side elevation with cover separated, Fig. 2 a top plan of the container body, Fig. 3 atop plan of'thecovenand Figs..-4 and 5 enlarged longitudinal sections atthe interlock.

The body of the container as shown'is eylin drical. and maybe understood to be formed of i wound paper-stock as usual and provided with any'suitable bottom, metal or otherwise as preferred. ,Its upper end is formed with an outwardly embossed circumferential stop-bead l and 4 a series, of outwardly embossed inclined ribs 2, above the stop-bead, spaced apart equally around the circumference, six of such ribs being shown with the spaces between them somewhat shorter than their own lengths. The bossing of the stock to form the bead and ribs is a well known process and can be performed in automatic machinery, the paper-stock being well sized or stiffened to enable it to retain the shape given to it by the bossing dies. It is to'be noted that by virtue of the circumferential separation of the inclined ribs no two of them are laterally adjacent so i that the displacement of stock incident to the embossing of one is not affected by the proximity of the other, thereby facilitating the formation of ribs with sharp well bossed contour.

The metal cover is formed with a depressed center 3 and a circumferential flange 4,.the latter being provided with a curled finish-bead 5 along its edge, and with a number of inwardly embossed inclined ribs 6 for screw'thread or interlocking engagement with the outwardly bossed paper ribs 2. When the cover is applied to the rim of the paper body and rotated, the metal ribs ride under the paper ribs and by virtue of their inclinations draw or lock the cover on the body, in which position its finish-bead 5 bears more or less on the stop-bead I, and the top of the annular groove, formed between the flange and the depressed part of the cover, seats on the top or cut edge of the paper rim. This produces a double seal for the container, one at the bead and .one at the edge, to prevent escape of its contents or entrance into it of foreign matter. It is not indispensable that the cover make simultaneous contact at both places but it is desirable and such construction is preferred.

The annular wall 1 which forms the inner wall of the annular groove just referred to is specially dimensioned'with relation to the paper body so that in the application of the cover, it bears snugly against the inner surface of the paper rim of the body and thereafter supports it against bending or yielding. inwardly, out of interlocking relation, thereby resisting the tendency for the metal ribs to ride over the paper ribs. For this purpose the wall 1 is desirably, though not necessarily, formed with a slight conicity as indicated. Fig. 5 illustrates this supporting function; from which it will be apparent that the paper rib must be virtually crushed-by the metal rib before the cover can be pulled on, and since the rib is well sized this action is effectually resisted.

The security of the attachment is increased by treating or coating the surfaces of the ribs, or more easily the surface of the whole rim above the stop-bead, to give it a greater friction coefllcient to metal than the paper stock alone would afford. This can be done in many ways as for example by dipping the rim in a lacquer of shellac in alcohol, or in an enamel, or in fact any kind of surface-coating material which is inexpensive ancLa non-lubricant, that is to say, upon which the metal ribs will not slide as easily as on the bare paper. The increased friction produced in this way does not objectionably or appreciably obstruct the rotation of the coveron the paper because then the ribs move endwise, but it does obstruct the riding of the metal ribs over the paper ribs because in that case the metal ribs must move sidewise. Increasing the friction thus favors security of attachmentlwithout otherwise afiecting the operation. In the ordinary case the metal wall which supports the paper rim against bending or yielding out of interlocking relation with the metal ribs can be produced most easily by depressing the center of the cover as commonly done in many forms of container covers, but so long as its described function is properly performed, the style or mechanical organization of the cover as well as the depth, location and shape of the wall it self will be seen to be relatively subordinate and to be determined according to circumstances.

It is a further feature of the invention that the metal ribs or projections onthe cover are cir.-.

cumferentially spaced from each other by short and uniform distances because this helps materially in preserving the paper rim from becoming distorted from true circularity by the force sometimes applied in screwing on the cover. In this respect the metal ribs supplement the functions of the stop-bead, and the support wallI. The number of ribs is subject to variation according to the body diameter, six being found satisfactory for body diameters ranging from two to six inches, being in each case circumferentially spaced from i each other by distances not greater than their own lengths and not greater than the spaces between the paper ribs. So organized the high ends of the metal ribs will occupy the spacesbetween the paper, ribs when the cover is screwed home thereby aiding in preserving circularity. This is indicated by the dotted lirie position of the metal ribs in 1. It will be seen that in performing this function it is not necessary that each one of the metal ribs shall interlock with mating paper ribs, whichris to say that the purpose of maintaining circularity can be accomplished. by

cover projections that are not ribs or inclined' ribs. It is preferred however that all of the projections be ribs adapted to interlock with corresponding paper ribs.

It is likewise important anda collateral feature of the invention that the angle of the metal and paper ribs be about 10 While lower angles are permissible within the limits of the invention, it has been found that-an angle of about this value, in combination with tither features of the new structure, practically removes all possibility of driving the metal ribs over'the paper ones even by the application of excessive screwing-on force, and at the same time adequately locks the cover against unscrewing itself.

All of the features above described cooperate in producing a superior lock-top container but to the extent that they are individually new they constitute parts of this invention usable in other relations as will be evident.

I claim: 1. A lock-top container comprising a paper body and metal cover respectively provided with ribs adapted to interlock,vthe cover including a with an annular wall engaging and supporting the inner side of the paper rim when so interlocked, said paper rim and the ribs thereon being impregnated with a non-lubricating material providing increased friction to the movement'of the metal ribs thereoverc 3. A lock=top container comprising an allpapei. body wall cut from tubular stock. and formed with an embossed stop-bead and a series -of inclined ribs circumferentially'spaced apart between said bead and the cut edge, and a cover having a metal flange provided with a finish bead and with mating ribs to coact with said stop bead and paper ribs respectively, and having a depressed center forming an annular wall for engaging and supporting the cut edge of said body wall when the cover is screwed home.

4. A lock-top container comprising an all-paper body wall cut from tubular stock and having its rim portion embossed with circumferentially spaced, inclined ribs and a metal cover formed with mating ribs to'interlock with said paper ribs and having a depressed center forming an annular wall adapted to engage the out edge of said body wall, said rimportion being covered with a non-lubricating coating and said metal ribs being of greater length than the paper ribs.

5. A lock-top container comprising an all-pal per body wall having :a circular stop-bead embossed therein below its out edge and a series of inclined ribs embossed above the bead, a flanged metal cover having a circular groove to receive said edge and a series of inclined ribs to interlock with the paper ribs, the cover and body parts being relatively dimensioned so that the bottom of the groove seats on the cut edge of the body when the flange of the cover abuts the stop-bead, thereby forming a double seal for the container.

6. A lock-top container comprising an all-paper body and a metal cover respectively provided with embossed inclined ribs adapted to interlock by rotary cover motion, the paper body being embossed with a circular bead below its inclined ribs and having a friction-increasing coating on said ribs, and said cover having an annular wall normally having a bearing contact with the inner side of the paper rim.

. MARTIN P. KERNAHAN. 

